Apparatus for refrigeration treatment

ABSTRACT

An apparatus for refrigeration treatment is used in cryomedical treatment for applying gas of extremely low temperature onto an affected portion of a patient. In the flow system of the apparatus, there are a liquefied gas source, a temperature controlled bath and a conduit pipe having a cup at its end to be placed over the affected portion. The bath contains a liquid medium of high specific heat in which are immersed a mixing cylinder and an evaporator which are mutually connected with a plurality of tubes. The liquefied gas supplied from the source to the evaporator is vaporized and flowed through the tubes to the cylinder where the vaporized gas is mixed with a liquefied gas directly supplied from the source at an optimum gas temperature.

This is a division of application Ser. No. 109,271 filed Jan. 3, 1980now U.S. Pat. No. 4,292,973, which is a division of Ser. No. 944,079filed Sept. 20, 1978 now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to an apparatus for refrigeration treatment,particularly to an apparatus by which cryogenic air is provided andapplied to an affected portion at high speed.

In medical treatment of sprains, rheumatism, contusions, neuralgia andother diseases, successful results are obtained by cooling and affectedportion with a cryogenic gas applied at high speed and in a short time.In this type of treatment it is sometimes required to apply a cryogenictemperature of -80° C. to -190° C. to an affected portion.

Generally, a simple method of obtaining a cryogenic temperature formedical treatment is to use ice or a refrigerant, but it does not offerthe cryogenic temperature and consequently, cryogenic air obtained froma refrigerator or cryogenic carbon dioxide gas obtained by blowing outliquefied carbon dioxide gas is used. However, it is not easy to obtainsuch cryogenic temperature as can meet the above requirement. If theapplication is simply to cool the affected portion, it is possible toapply liquefied gas to the affected portion by utilizing the cryogeniclatent heat produced in vaporization of liquefied gases such as liquidoxygen (boiling point -183° C.) or liquid nitrogen (boiling point -196°C.).

If these gases are used for medical treatment in a small treatment roomhowever, the room will be filled with gas. The former gas may involvethe danger of fire and the latter gas may cause lack of oxygen in theroom. Thus, it is not desirable to use these gases for medical treatmentin the manner mentioned above.

SUMMARY OF THE INVENTION

The present inventors decided to utilize commercially availableliquefied air, which would cause no harm to individuals even when it isused in a room and fills the room and yet produces appropriate effectsof refrigeration treatment of an affected portion and which is availableat a relatively low cost. To refrigerate an affected portion for medicaltreatment, it is necessary to change the cooling temperature to beapplied to the affected portion in accordance with the degree of thedisease or ailment. Furthermore, for efficient treatment of same, it isalso necessary to be able to change the refrigerating gas temperature ina short time in the preparation of the medical treatment. This requiresobtaining air of the aforementioned optimum temperature of -80° C. to-190° C. suitable for medical treatment in a short time by producingcryogenic air from liquefied air, whose boiling point temperature isapproximately -193° C. Liquefied air is obtainable from liquefied oxygenand liquid nitrogen by mixing these liquid gases at approximately thesame mixing ratio as that of oxygen to nitrogen in the air. Butgenerally speaking, it is difficult to rapidly change the temperature oflow temperature air in such wide range of temperature.

In our daily life, when water poured into a cup is too hot for drinkingor gargling, we cool it by adding cold water into the cup to make thetemperature suitable for drinking or gargling, instead of waiting forthe hot wter to cool naturally. Based on this principle, the presentinventors carried out experiments, assuming that air below theaforementioned temperature of -80° C. suitable for medical treatmentwould be obtained by mixing ordinary atmospheric air with cryogenic airwhich has just vaporized.

Air of the intended optimum cryogenic temperature can be obtained inthis manner. In order to apply the cryogenic air thus-obtained to anaffected portion, it is necessary to introduce the cryogenic air into aconduit or hose and apply this cryogenic air to the affected portionthrough a cup provided on the end of the conduit. Since air in theatmosphere contains moisture, however, moisture in the atmospheric airwill be mixed with the cryogenic air and clog the conduit with themositure frozen in the conduit, thus making it impossible to blow outthe gas from the cup. Furthermore, when the mixed cryogenic air is blownonto the affected portion, moisture in the mixed gas will freeze theaffected portion upon contact therewith. This makes it necessary toremove the moisture in the warmer air. Removal of moisture in theatmosphere can be accomplished by use of a dehumidifier. To removemoisture completely by this dehumidifier, it must be installed in thetreatment room or in an adjacent room in use. It is, however,troublesome for a doctor engaged in medical treatment or an assistantdoctor or nurse to supervise the operation of this apparatus. Sincemoisture has been removed from liquefied air, sold on the market, duringits liquefying process, there is no moisture to freeze when gas obtainedby vaporizing liquefied air is introduced into a conduit. The presentinvention was made by taking advantage of this point. If the conduit forfeeding the cryogenic gas takes a long time to apply such a cryogenicgas to an affected portion, the conduit is heated by the temperature ofthe room in which treatment is made, with the result that thetemperature of the gas discharged or blown out from the end of theconduit increases. It is therefore necessary to make the length of theconduit to feed the gas as short as possible. However, even theslightest carelessness may allow liquid gas not yet vaporized to reachthe affected portion. This also involves danger.

The present invention was made with this problem taken into account andis provided with an evaporating apparatus for evaporating liquid intogas by introducing liquefied gas into a flow path, in the flow path forfeeding cryogenic gas which has been vaporized in a conduit byvaporizing liquid discharged from the reservoir of the liquid gas intothe conduit in the form of liquid, the evaporating apparatus being soconstructed that a valve mechanism is provided to prevent inflow of theliquid into the evaporating apparatus when the liquid of the liquid gasfed to the apparatus reaches a specified volume. In the valve mechanismthere is used an electromagnetic valve, check valve or the like designedto prevent inflow of excessive liquid into the evaporating apparatus sothat a large amount of fluid fed to the evaporating apparatus fromupstream, i.e., from the reservoir in the form of liquid, does not flowdownstream from the apparatus in the form of liquid without beingvaporized completely in the evaporating apparatus.

On the downstream end of the flow path to feed the cryogenic gas of therefrigeration treatment apparatus according to the present invention, acup is provided for application to the affected portion of a patient ina prone position of kneeling down on one knee. Here, the flow pathconnecting to the cup may preferably be a flexible tube, and rubber orplastic material which is a flexible and thermally insulating materialat ambient temperature cannot maintain flexibility at the cryogenictemperature mentioned above. Furthermore, a conduit to be used at such acryogenic temperature is large in outside diameter through small ininside diameter, because the insulating layer surrounding the conduit isthick. It is hardly possible to expect such a conduit to be flexible.Instead, it is rigid. Thus, the flow path in the present invention isprovided, on the flow path end to which the cup is directly fitted andin the upstream rigid flow path portion, with at least one set of jointassemblage comprising the firt joint which turns around the flow pathaxis and air-tightly communicates with the flow path and the secondjoint which turns in the plane intersecting the axis of the joint atright angles and which air-tightly communicates with the first joint toform a flow path toward downstream.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing the general arrangement of theapparatus according to present invention;

FIG. 2 is a schematic diagram showing the evaporating mechanism of theliquid gas;

FIG. 3 is a schematic diagram of another evaporating mechanism accordingto the present invention;

FIG. 4 is a schematic diagram of still another evaporating mechanismaccording to the present invention;

FIG. 5 and FIG. 6 are vertical sections of the joint mechanism; and

FIG. 7 is a perspective view of the conduit mechanism at the end wheregas is required.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The liquid gas source of air, oxygen or nitrogen is housed in a vessel(3), the vessel (3) being surrounded by a protective cylinder and heatinsulating material (3a) is filled between the vessel (3) and theprotective cylinder for heat retention. Two branched exhaust tubes (5)are provided at the discharge port (4) of the vessel (3) via open-closevalve (16), and the exhaust tube (5) is branched into tubes (5a) and(5b). Between the valve (16) and the discharge port (4) is provided abranch path to a safety valve (14), which is further branched to returnto the vessel (3) via a liquid gas discharge pressure regulation valve(15). The tubes (5a), (5b) are connected to the evaporator and mixingcylinder of a temperature controlled bath (6) via gas dischargeregulators (17a), (17b), respectively. The temperature controlled bath(6) is filled with a liquid medium (7) having higher specific heat suchas water or a mixture of water and alcohol and the medium (7) is heatedby a heating apparatus such as an electric heater (8) from under thebath (7). The evaporator and a mixing cylinder (11) communicate witheach other by means of a plurality of heat exchange tubes (10) via themedium (7). The outlet side of the mixing cylinder (11) is a dischargeport (12), which connectes to a conduit (2) connected to a cup (1) to beapplied to an affected portion. The conduit (2) is a covered tube orcovered conduit with heat insulating materials for heat retention. Theend of the conduit (2) is connected to the cup (1) via a non-return-typeexpansion valve (19).

Operation of the apparatus in FIG. 1 is described below. First, valve(16) is opened to feed vapour into the exhaust tube (5), and the flowrate of the evaporated gas flowing through tubes (5a) and (5b) isregulated by properly adjusting the regulators (17a) and (17b). Toincrease the temperature of the cooling gas to be used, the flow rate ofthe gas fed through the tube (5a) is increased and to make thetemperature relatively low, the flow rate for the tube (5b) isdecreased. Filter (21) is installed in the conduit (5) to remove smallpieces of ice, dust particles and other foreign objects contained in theliquefied gas. The discharge port (12) connects to a conduit (2)connected to a cup (1) to be applied to an affected portion. The conduit(2) is a tube or conduit covered with a heat insulating material (18)for heat retention. The end of the conduit (2) is connected to the cup(1) via a non-return-type expansion valve (19). One important point ofthis embodiment is the provision of an evaporating apparatus comprisingan electromagnetic valve (22) installed in the conduit (5) downstream ofthe filter (21) and an evaporating chamber (23) installed in the conduit(5) downstream of the valve (22). In the evaporating chamber (23) isprovided a detecting float (24) which floats in the liquefied gas fedfrom the reservoir (13) through the conduit (5). This float is sodesigned that it rises in the evaporating chamber (23) with rise of theliquefied level when the liquid gas fed into the evaporating chamber(23) accumulates to a specified volume to raise the level and generatesan electric signal when it comes in contact with, for example, theceiling of the evaporating chamber (23) or the like. When the liquefiedgas fed to the evaporating chamber (23) accumulates in the chamber (23)and is heated by the temperature of the external air and other airthrough the evaporating chamber wall, the liquefied gas vaporizes andthe vaporized gas flows downstream from the outlet (12) of theevaporating chamber (23) through the conduit (2).

Describing the actions of the evaporating apparatus mentioned above, theliquefied gas discharged from the reservoir (13) in the form of liquidpasses through the conduit (5) and enters the evaporating chamber (23)through the electromagnetic valve (22) which is normally open. Theliquid gas is vaporized in the evaporating chamber (23), heated by theoutside air as mentioned above, and flows downstream from the outlet ofthe evaporating chamber (23), for example, toward the conduit end wherethe cup (1) is provided. As long as the liquefied gas is demandedcontinuously at the conduit end, the liquefied gas flows smoothly intothe evaporating chamber (23) and is evaporated in the chamber (23) to bedischarged downstream. However, the liquid may flow excessively into theevaporating chamber (23) for some reason. In this case, the liquid fedto the evaporating chamber (23) constantly accumulates in the chamber(23). As the liquid accumulates in the evaporating chamber (23), thefloat (24) rises with rise of the liquid level until it comes in contactwith, for example, the ceiling of the evaporating chamber or anotherarea of the chamber (23) and generates an electrical signal, thereby theelectromagnetic valve (22) is closed to prevent the liquefied gas fromthe reservoir (13) from flowing into the evaporating chamber (23). Ifthe electromagnetic valve (22) is not closed in this case, the liquefiedgas will gush out from the cup in the form of liquid, causing serioustrouble. If the vaporized gas does not flow smoothly downstream, theinternal pressure of the evaporating chamber (23) will increase by thepressure of the vaporized gas. Although this increased pressure sofunctions as to push back the liquefied gas fed to the evaporatingchamber (23) to the reservoir (13), with further increase in pressurethe pressurized gas will flow into the reservoir (13), causing an abruptincrease of the reservoir pressure and large quantities of liquefied gasin the reservoir (13) to gush out. However, this evaporating apparatusdetects only the rise of the liquid level of the evaporating chamber(23) and closes the electromagnetic valve (22) by the signal the floatsends out when a specified liquefied level is reached, so that theliquefied gas does not flow back upstream and the liquid gas in thereservoir (13) is prevented from gushing out. Since the circuitry andmechanism for operating the electromagnetic valve (22) by a signalproduced by the float (24) can be created by those skilled in the artwithout inventive conception, details of same have been omitted. In anembodiment other than the above embodiment, where the liquefied gas inthe evaporating chamber (23) has a temperature difference between agaseous state and a liquid state, a resistor element, whose electricresistance changes with changes of temperature due to the endothermicdifference caused by the difference of substances, is arranged in such amanner that it is in contact with the gas at all times and comes incontact with the liquid if the liquid level in the evaporating chamberrises. In this manner, when the resistor element in the gaseousatmosphere comes in contact with the liquid, a signal is generated bythe change in resistance and the electromagnetic valve (22) can beclosed by this signal. This structure does not make it necessary toplace the evaporating chamber (23) in a horizontal position for correctoperation of the float floating in the liquid. FIG. 2 is a schematicillustration of another evaporating apparatus, in which evaporatingchamber (23) is provided in conduit (5). Upstream of this evaporatingchamber is provided a check valve (25) and the liquid fed through theconduit (5) flows into the evaporating chamber (23) from an inflow path(5a) through valve (25). The gas vaporized in the evaporating chamber(23) is fed to the extension portion (2) of the conduit (5) from theoutlet (26) through the outflow path (12). In the area under the outflowport (26) there is an enclosure (27) such as a grid or the like, inwhich float (28) is placed. The inflow port (29) of the inflow path (5a)is opened below the outlet (26). The float (28) floats in th liquid fedto the evaporating chamber (23) and rises with the rise of the liquidlevel so as to block the outlet (26). Numeral (30) is a pressure valveclosed at all times, which is installed in a bypass (31) connecting theevaporating chamber (23) with the downstream conduit (2). Describing theactions of this embodiment, the liquid gas discharged from the reservoir(13) is fed from the conduit (5) to the evaporating chamber (23) throughthe check valve (25). Since the inflow port (29) of the inflow path (5a)is opened in the lower portion, the port (29) is immersed in the liquidwhen the liquid accumulates in the evaporating chamber (23) so that thegas vaporized in the evaporating chamber (23) does not fill the inflowpath (5a). The gas vaporized in the evaporating chamber (23) flowsdownstream from the outlet (26) through the outflow path (12). Here, ifthe inflow of the liquid becomes excessive for some reason, the liquidfed from the inflow path (5a) accumulates in the evaporating chamber(23), causing the liquid level to rise. With this, the float (28) risesand blocks the outflow port to prevent the liquefied gas from flowingout of the outflow path (12). The vaporized gas in the evaporatingchamber (23) is thus pressurized, causing the liquid level to becompressed by the pressurizing force and the liquid is in a state toflow back from the inflow port (29) to the inflow path (5a). Here,however, the check valve (25) prevents the liquid from flowing backupstream. At the same time, the pressure in the evaporating chamber (23)increases gradually until it reaches a specified pressure, when thevalve (30) operates to feed the gas partially to the bypass (31) todischarge it downstream. Thus, the gas pressure drops and the liquidlevel lowers to restore the original steady state. Accordingly, theliquefied gas is prevented from directly flowing downstream.

The evaporating apparatus described in reference to FIG. 1 is used byfurther improvement as shown by FIG. 3. The flow path from the liquidgas container (13) to the electromagnetic valve (22) is the same as thatof the embodiment in FIG. 1 above, while the conduit (5) downstream ofthe electromagnetic valve is divided into two branches, (5b) and (5c).The conduit (5d) is provided with check valve (33), liquefied gas flowrate regulator (34) and liquefied gas evaporating apparatus (35) andmerges into the branch conduit (5c) downstream of the evaporatingapparatus (35). The conduit (5e) is provided with regulator (36) of theliquid gas flowing in the conduit (5c) midway thereof. The conduit (5e)merges into the downstream conduit (5e) in a nozzle shape downstream ofthe evaporating chamber (35) to form a gas-liquid mixing chamber (37).Downstream of the mixing chamber (37) is gas-liquid separating chamber(38), whose outlet is the discharge pot (12) and connects to the conduit(2) for treatment of an affected portion by means of connecting pipe(40). The evaporating chamber (35) and gas-liquid separating chamber(38) are so designed that they are heated externally so as to evaporatethe liquefied gas. The separating chamber (38) and discharge port (12)are provided with a liquid detector (39) and thermometer (41); and aheater in the evaporating chamber (35) is operated so as to keep thetemperature of vaporized liquefied air flowing from the (5b) side abovea certain temperature.

The following description is the operation of the evaporating apparatusshown in FIG. 3. As described in reference to the embodiment shown inFIG. 1, the flow of the liquid up to the electromagnetic valve (22) isthe same, and part of the liquid that passes through the valve (22) isfed to the evaporating chamber (35) through check valve (33) and flowrate regulator (34). The chamber (35) is heated by a heater and theliquefied gas is vaporized in the chamber (35) and fed to the mixingchamber (37). On the other hand, part of the liquid that passes throughthe valve (22) is fed to conduit (5c) and to the mixing chamber throughflow rate regulator (36). The conduit (5c) is opened in a nozzle shapein the mixing chamber (37) and the velocity of the liquid flowing fromthe nozzle-shaped discharge port into the mixing chamber is not great.On the other hand, the flow velocity of the liquid vaporized in theevaporating chamber (35) is so great due to volumetric increase duringto gasification that the liquid flowing in the conduit (5c) is atomizedby the liquid flowing in the conduit (5c) and enters the mixing chamber(37), forming a mixture of gas and atomized particles. The mixed fluidis fed to the gas-liquid separating chamber (38) and the gas accumulatesin the upper part of the chamber (38) and the fine particles of liquidat the bottom thereof. Here, the gas fed from the evaporating chamber(35) to the mixing chamber (37) in the form of gas is heatedconsiderably, say, -90° C. to 140° C., but is cooled down to a specifiedcryogenic temperature, say, to -170° C. by being mixed with the liquidin the mixing chamber and is fed to the separating chamber (38). Thenthe mixture is separated into gas and liquid by specific gravity andviscosity etc. in the separating chamber (38) and the gas is cooled downto a specified temperature to be fed from the discharge port (12) to theconduit (2) through the connecting pipe (40). If the liquid accumulatesin the bottom of the separating chamber (38) and is not evaporatedcompletely, the detector (39) detects same and causes the separatingchamber (38) to be heated by a heater to evaporate the liquid gas. Thedischarge port (12) is provided with a temperature sensor (41) toactuate the heater element of the evaporating chamber (35) in accordancewith the temperature of the gas passing through the discharge port (12).In this manner, the liquid passing through the conduit (5b) cannot onlybe vaporized rapidly, but also the liquid passing through the conduit(5c) not heated can be mixed with the vaporized gas in the form of vaporat cryogenic temperature and the temperature of the overheated gas canbe lowered rapidly to a specified temperature; thereby gas for medicaltreatment of an affected portion can be prepared rapidly. As referred toin the preceding paragraph, the vaporized gas is as low as -170° C. intemperature. For the conduit for feeding the gas, a rigid tube is used,as mentioned in the foregoing paragraph. On one end of the rigid tube isprovided the cup (1), and mechanisms illustrated in FIGS. 5 to 7 areused to bring the cup (1) close to the affected portion of a patient ina stationary position. In FIG. 5, numerals (45) and (46) are hollowjoint tubes to be installed by alignment and a ring-shaped packing (48)of smooth, elastic material such as polytetra fluoroethylene is providedon the shoulder (47) of the joint (45) on the side where both jointsface each other and both joints are joined oppositely with packing therebetween. Ring-shaped packing (50), similar to the packing (48) isprovided on the shoulder (49) of the joint (45) on the side opposite thepacking (48), and washer (51) and coiled spring (52) are placed on thepacking (50). Here, both joints are joined by fitting the pot-shapedcylindrical union (53), whose inner wall is partially threaded, to thethreaded portion of the outer wall of the joint (46), with the innerbottom of the pot (53) urged toward the spring (52). This makes thejoint (45) coaxial with the joint (46) and allows it to rotate withrespect to the joint (46). To describe another joint further, referringto FIG. 6, ring-shaped packing (56) similar to the above is provided onthe shoulder in the upper part of the hollow joint (55), and hollowspherical body (57) which can be made coaxial with the hollow axis ofthe joint (55) is laid on the joint (55). The joint (55) is joined withthe spherical body (47) in such a manner that after arranging the otherring-shaped packing (58) around the spherical body on the opposite sideof the packing (56), arranging snap ring (59) having inwardly andoutwardly directed flanges on both sides, respectively, around thepacking, and arranging coiled spring (61) by placing it on the outwardlydirected flange (60) on the outside periphery of the ring (59), thepot-shaped cylindrical union (62) is inserted from the side of thespherical body (57) to fit the thread on the inner wall of the unioninto the thread of the outer wall of the joint (55). The spherical bodyhas a protrusion of a hollow cylinder (63) in the longitudinal directionof the hollow shaft and the cylinder is fitted with jet pipe (64) whichforms and integral part of the cup (1). In this mechanism, the integralpart of the spherical body (57) and cylinder (63) along with the joint(55) forms a spherical joint and not only revolves around the joint axisbut also can make conical movement with respect to the center of thespherical body so long as the cylinder (63) is in contact with the ring(59).

FIG. 7 is a schematic illustration of the joint fitted to the endmechanism, in whcih stand (70) is provided on the end of the conduit (2)in such a manner that it is air-tight to the conduit (2) and can turnaround the conduit axis. If stand (71) is installed, in the samerelationship as the joints (45) and (46) in FIG. 5, with respect to thestand (70), the rigid conduit (72) which protrudes from the stand (71)intersecting the conduit (2) at right angles can take athree-dimensional position with respect to the conduit (2). By arrangingthe stand (73) and stand (74) installed on the end of the conduit (72)in the same relationship as stands (70) and (71), the rigid conduit (75)protruding air-tightly from the stand (74) can be brought close to theaffected portion of a patient with respect to the conduit (2). Furtherprovision of the mechanism illustrated in FIG. 6 on the end of theconduit (75) makes it possible to spary cryogenic gas by moving the cuparound the leg or knee of a patient in a prone position.

As described above, the art of the present invention vaporizes liquidgas from a liquid gas reservoir by an evaporating apparatus in aposition near the end where treatment is to be made and supplies thevaporized gas from any three-dimensional direction in the required areaon the end by using rigid conduits, thus shortening the gas feedingdistance from the evaporating apparatus to the required place. Ifexcessive liquid gas should be fed to the evaporating apparatus, theflow rate of the liquid fed is immediately detected in the evaporatingchamber and if the rate reaches a specified rate, the valve mechanismupstream of the evaporating chamber is closed so that the liquid gasdoes not flow out to the downstream required place before it isvaporized. Here, the liquid fed from the reservoir to the evaporatingchamber by the pressure of further vaporized gas is prevented from beingforced to return to the reservoir by compression, thereby the liquid inthe reservoir being prevented from gushing out wastefully. Furthermore,the gas to be applied to the affected portion can be prepared in a veryshort time and the treatment can be performed very efficiently. Theabove description of the invention is intended to be illustrative andnot limiting. Various changes or modifications in the embodimentsdescribed may occur to those skilled in the art and these can be madewithout departing from the spirit or scope of the invention as set forthin the claims.

We claim:
 1. An apparatus for refrigeration treatment comprising aliquefied gas source, an evaporator for evaporating the liquefied gas atan optimum temperature, an exhaust tube connected between said gassource and said evaporator to conduct the liquefied gas from said gassource to said evaporator, a conduit for introducing the gas vaporizedby said evaporator and being connected to said evaporator by means of anoutflow port, and a cup provided with a non-return expansion valveattached at the end of said conduit, said cup adapted to apply saidvaporized gas to an affected portion of a patient in order torefrigerate said portion with said vaporized gas, said evaporator beingprovided with an evaporator chamber in which said liquid is accomodatedand then evaporated by heat conduction from the wall surface thereof forevaporating the liquefied gas to a gaseous state to be blown out fromthe cup at a specified temperature and wherein said evaporator isprovided with a first flow path having the evaporating chamber thereinand a second flow path, said apparatus further comprising a mixingcylinder at the outlets of said evaporating chamber and said second flowpath, the liquid and gas flowing through the respective paths beingmixed in a spray in said mixing cylinder, and said exhaust tubecomprises a valve for preventing the inflow of liquefied gas into saidevaporating chamber when the liquid of the liquefied gas fed to saidevaporating chamber reaches a specified flow rate.
 2. An apparatus forrefrigeration treatment set forth in claim 1, further comprising agas-liquid separator adjacent said mixing cylinder to separate the gasfrom said spray.
 3. An apparatus for refrigeration treatment as claimedin claim 1 or 2 wherein said conduit is a flexible conduit.